A configuration of such a component is known from the published European patent application EP 616 243. It describes an optical space switch which contains optical waveguides with active, i.e. controlled light-amplifying or light-absorbing waveguide sections, and passive waveguide sections, i.e. which conduct unamplified light. The optical waveguides contain a semiconductor layer structure whose layers have a different layer thickness in the active waveguide sections than in the passive waveguide sections. A process is also indicated whereby the active and passive waveguide sections can be deposited in a single coating process. This process utilizes the fact that no semiconductor material grows on substrate areas coated with a dielectric layer, and that the growing rate between sections masked with a dielectric layer increases as a function of the size of the adjacent masked surface.
The described optical space switch however has the disadvantage that its operation is polarization-dependent, i.e. light signals of different polarization directions receive different amplification or are absorbed in the active waveguide sections.
In addition, a wavelength converter with continuous active waveguides is known from an article by M. Schilling et al: "Wavelength converter based on an integrated all-active three-port Mach-Zehnder interferometer", El. Lett. Vol. 30 No. 25, 1994. This semiconductor component is also polarization-dependent and needs an expensive control with high power consumption for the different active waveguide sections.
An article by M. Aoki et al: "New Photonic Device Integration by Selective-Area MOVPE and Its Application to Optical Modulator/Laser Integration", IEEE Microw. and Opt. Tech. Let. Vol. 7, No. 3, 1994, describes in detail the method used in patent application EP 616243, which is known under the name of Selective Area Growth (SAG), for the example of a monolithic integrated semiconductor component with a laser and a modulator. So-called multiple quantum well structures are used as semiconductor layer structures which are semiconductor layers with alternately small and wide energy gaps. Energy gap means the energy difference between the valence band and the conductivity band of the semiconductor. The article recommends the process for the monolithic integration of a line of other components, particularly for photonic integrated circuits. However, the components manufactured in accordance with this process also have the disadvantage that they are polarization-dependent.
A further article by G. Coudenys et al: "Novel Growth Techniques for the Fabrication of Photonic Integrated Circuits", Mat. Res. Symp. Proc. Vol. 240, 1992, pages 15-26 cites a disadvantage of the selective area growth method in that the composition of the material of the growing semiconductor material, and therefore its lattice constant, changes in lateral sections masked with a dielectric layer.
An article by M. Joma et al: "Polarization Insensitive Semiconductor Laser Amplifiers with Tensile Strained InGaAsP/InGaAsP Multiple Quantum Well Structure", Appl. Phys. Lett. Vol. 62(2), pages 121-122, 1993, describes an optical amplifier with active tensile-strained multiple quantum well structures which operates independently of the polarization. This component however contains no passive waveguide sections and is manufactured in accordance with a process which does not enable the integration with passive waveguide sections.